Preparation Of CoB-based Catalyst By Magnetic Field Induction And Study On Its Performance In Water Splliting

Electrocatalytic water decomposition（EWS）is a promising and sustainable method for hydrogen production.In order to realize large-scale EWS hydrogen production,it is necessary to develop high catalytic activity,low cost and good durability electric catalysts.In recent years,CoB-based compounds are becoming promising candidates for the EWS process due to their simple synthesis and low cost.However,CoB-based compounds still face two main challenges:one is the uncontrollable preparation process and serious agglomeration;the other is the low density of surface actives sites.Therefore,preparing a CoB-based catalyst with a controllable morphology and increasing its exposed active sites have become the key to solving the problem.Here,by means of magnetic field induction,a one-dimensional chain-like CoB nano-alloy was obtained,and the catalytic water splitting performance of the CoB catalyst was greatly improved by compounding with a substance with high catalytic activity.This thesis consists of three parts.The main contents are as follows:（1）CoB nano-alloy with the shape of nanochain was prepared by reducing cobalt chloride with sodium borohydride assisted by external magnetic field.On this basis,ultrathin Ni（OH）₂ nanosheets were grown on the surface of CoB alloy by means of cationic etching.The material was characterized by SEM,TEM,XRD,XPS,BET and other physical and electrochemical tests.The results show that Ni（OH）₂@CoB catalyst shows good catalytic activity and stability in the catalytic oxygen evolution reaction（OER）.（2）On the basis of the first part of the work,nickel-iron layered double hydroxide（Ni Fe LDH）network was successful growth on the surface of the CoB by introducing of oxidizing stronger Fe³⁺.XRD,XPS,SEM,TEM,contact angle test and other physical and electrochemical characterizations have been carried out.The results show that the prepared heterojunction Ni Fe LDH@CoB catalyst has excellent catalytic activity and stability in catalyzing OER reaction.（3）In the first two parts of the work,the OER performance of the material has been significantly improved,but the catalytic hydrogen evolution reaction（HER）performance is not satisfactory.In order to improve the overall water splitting performance of the material,the preparation of Co P@CoB catalyst was synthesized through the strategy of gas phase phosphating with the Kirkendall effect.The results of SEM,TEM,XRD,XPS and electrochemical tests prove that the adaptive growth of cobalt phosphide,which has a strong adsorption effect on H⁺,on the surface of CoB improves the performance of CoB’s catalytic hydrogen evolution reaction（HER）.